Living body observation device

ABSTRACT

A light source unit, which is connected to a control unit and an endoscope, radiates a pre-determined light quantity of white light based on a signal from the control unit. The light source unit includes a lamp as a white light source, an infrared cut filter, a light quantity limiting filter, being inserted/removed on an optical path, for limiting light quantity in a pre-determined wavelength region of white light, a filter insertion/removal driving unit for inserting/removing the light quantity limiting filter on an optical path, and a condensing lens for outputting white light. For example, when a transmission rate of a blue band is 100%, the light quantity limiting filter limits transmission rates of other bands to 50%. This improves S/N in discrete spectral image generation with illumination light in a visible light region.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of PCT/JP2007/053088filed on Feb. 20, 2007 and claims benefit of Japanese Application No.2006-073183 filed in Japan on Mar. 16, 2006, the entire contents ofwhich are incorporated herein by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a living body observation device forusing a color image signal obtained by picking up an image of a livingbody to display the image as a spectral image on a display device bysignal processing.

2. Description of the Related Art

Conventionally, an endoscope device for obtaining an endoscope image ina body cavity by radiating illumination light is widely used as a livingbody observation device. This kind of endoscope device uses anelectronic endoscope including an image pickup unit for guidingillumination light from a light source into a body cavity using a lightguide and picking up an image of a shooting object by optical feedbackof the light. Such device processes an image pickup signal from theimage pickup unit by a video processor to display an endoscope image onan observation monitor and observe an observed part such as a diseasedpart.

As one scheme in performing normal observation of living tissue by anendoscope device, a light source emits white light in a visible lightregion, and irradiates an shooting object with frame sequential lightvia an RGB rotating filter, for example, and a video processorsynchronizes optical feedback of the frame sequential light andprocesses an image to obtain a color image. As another scheme inperforming normal observation of living tissue by the endoscope device,color chips are arranged on a front surface of an image pickup surfaceof the image pickup unit of the endoscope, the light source emits whitelight in a visible light region and the color chips separate opticalfeedback of the white light into respective color components to pick upan image, and the video processor processes an image to obtain a colorimage.

Living tissue has different light absorption characteristics andscattering characteristics depending on wavelengths of radiated light.As such, Japanese Patent Application Laid-Open Publication No.2002-95635, for example, discloses a narrowband-light endoscope devicefor irradiating living tissue with illumination light in a visible lightregion as narrowband RGB frame sequential light with discrete spectralcharacteristics and obtaining tissue information of a desired deep partof the living tissue.

Japanese Patent Application Laid-Open Publication No. 2003-93336discloses a narrowband-light endoscope device for processing an imagesignal with illumination light in a visible light region, generating adiscrete spectral image, and obtaining tissue information of a desireddeep part of living tissue.

In the device according to Japanese Patent Application Laid-OpenPublication No. 2003-93336, a light quantity control unit performsprocessing to decrease illumination light quantity to obtain a spectralimage (for example, illumination light radiation timing control, lightchopper control, lamp application current control or electronic shuttercontrol) for the illumination light quantity to obtain a normal lightobservation image, and controls to avoid saturation of a CCD being animage pickup unit.

SUMMARY OF THE INVENTION

A living body observation device according to one aspect of the presentinvention is a living body observation device comprising a signalprocessing control unit for controlling operation of an illuminationsource for irradiating a living body being a subject with light and/oran image pickup unit for photoelectrically converting light reflectedfrom the living body based on the illumination light from theillumination source and for generating an image pickup signal, and foroutputting the image pickup signal to a display device, the living bodyobservation device including:

a spectral signal generation unit for generating a spectral signalcorresponding to a band image of a discrete spectral distribution ofsaid subject from the image pickup signal by signal processing; and

a color adjustment unit for adjusting a color tone for each of aplurality of bands forming the spectral signal when the spectral signalis outputted to the display device,

wherein a spectral characteristics control unit for controlling spectralcharacteristics of light on an optical path is further provided on theoptical path from the illumination source to the image pickup unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outline view showing an appearance of an electronicendoscope device according to a first embodiment of the presentinvention;

FIG. 2 is a block diagram showing configuration of the electronicendoscope device in FIG. 1;

FIG. 3 is a diagram showing transmission characteristics of a lightquantity limiting filter in FIG. 2;

FIG. 4 is a diagram showing arrangement of color filters provided on afront surface of a CCD in FIG. 2;

FIG. 5 is a diagram illustrating a matrix calculation method ofcalculating a matrix in a matrix operation unit in FIG. 2;

FIG. 6 is a diagram showing spectral characteristics of spectral imagesgenerated by the matrix operation unit in FIG. 2;

FIG. 7 is a diagram showing a structure in a layer direction of livingtissue observed by an electronic endoscope device in FIG. 2;

FIG. 8 is a diagram illustrating a state of illumination light from theelectronic endoscope device in FIG. 2 reaching living tissue in thelayer direction;

FIG. 9 is a diagram showing spectral characteristics of each band of RGBlight during normal observation by the electronic endoscope device inFIG. 2;

FIG. 10 is a first diagram showing a band image with RGB light duringthe normal observation in FIG. 9;

FIG. 11 is a second diagram showing a band image with RGB light duringthe normal observation in FIG. 9;

FIG. 12 is a third diagram showing a band image with RGB light duringthe normal observation in FIG. 9;

FIG. 13 is a first diagram showing one of the spectral images in FIG. 6;

FIG. 14 is a second diagram showing one of the spectral images in FIG.6;

FIG. 15 is a third diagram showing one of the spectral images in FIG. 6;

FIG. 16 is a first diagram illustrating a graphic user interface with afunction of a touch-sensitive panel in FIG. 2;

FIG. 17 is a second diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 18 is a third diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 19 is a fourth diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 20 is a fifth diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 21 is a sixth diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 22 is a seventh diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2;

FIG. 23 is an eighth diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2;

FIG. 24 is a ninth diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 25 is a tenth diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2;

FIG. 26 is an eleventh diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2;

FIG. 27 is a twelfth diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2;

FIG. 28 is a diagram illustrating white balance processing on a spectralimage generated by the matrix operation unit in FIG. 2;

FIG. 29 is a thirteenth diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2;

FIG. 30 is a fourteenth diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2;

FIG. 31 is a diagram showing configuration of board slots on a backsurface of a main body of the endoscope device in FIG. 1;

FIG. 32 is a first diagram illustrating an additional function menu of afunction expansion substrate inserted into a board slot in FIG. 31;

FIG. 33 is a second diagram illustrating an additional function menu ofa function expansion substrate inserted into the board slot in FIG. 31;

FIG. 34 is a third diagram illustrating an additional function menu of afunction expansion substrate inserted into the board slot in FIG. 31;

FIG. 35 is a diagram showing one example of a keyboard dedicated towavelength selection that can be connected to the main body of theendoscope device in FIG. 2;

FIG. 36 is a diagram showing arrangement in a variation of the colorfilters in FIG. 4;

FIG. 37 is a block diagram showing configuration of an electronicendoscope device according to a second embodiment of the presentinvention;

FIG. 38 is a diagram showing configuration of an RGB rotating filter inFIG. 37;

FIG. 39 is a diagram showing spectral characteristics of light that istransmitted through the ROB rotating filter in FIG. 38 when a lightquantity limiting filter in a first spectral image generation mode isnot on an optical path;

FIG. 40 is a diagram showing spectral characteristics of light that istransmitted through the RGB rotating filter in FIG. 38 when the lightquantity limiting filter in a second spectral image generation mode ison an optical path;

FIG. 41 is a block diagram showing configuration of a variation of theelectronic endoscope device in FIG. 37;

FIG. 42 is a diagram showing configuration of an RGB rotating filter inFIG. 41; and

FIG. 43 is a diagram showing configuration of a variation of the RGBrotating filter in FIG. 37.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The following will describe embodiments of the present invention withreference to the drawings.

First Embodiment

FIGS. 1 to 36 relate to a first embodiment of the present invention.FIG. 1 is an outline view showing an appearance of an electronicendoscope device; FIG. 2 is a block diagram showing configuration of theelectronic endoscope device in FIG. 1; FIG. 3 is a diagram showingtransmission characteristics of a light quantity limiting filter in FIG.2; FIG. 4 is a diagram showing arrangement of color filters provided ona front surface of a CCD in FIG. 2; FIG. 5 is a diagram illustrating amatrix calculation method of calculating a matrix in a matrix operationunit in FIG. 2; FIG. 6 is a diagram showing spectral characteristics ofspectral images generated by the matrix operation unit in FIG. 2; FIG. 7is a diagram showing a structure in a layer direction of living tissueobserved by an electronic endoscope device in FIG. 2; FIG. 8 is adiagram illustrating a state of illumination light from the electronicendoscope device in FIG. 2 reaching living tissue in the layerdirection; FIG. 9 is a diagram showing spectral characteristics of eachband of RGB light during normal observation by the electronic endoscopedevice in FIG. 2; and FIG. 10 is a first diagram showing a band imagewith RGB light during the normal observation in FIG. 9.

FIG. 11 is a second diagram showing a band image with RGB light duringthe normal observation in FIG. 9; FIG. 12 is a third diagram showing aband image with RGB light during the normal observation in FIG. 9; FIG.13 is a first diagram showing one of the spectral images in FIG. 6; FIG.14 is a second diagram showing one of the spectral images in FIG. 6;FIG. 15 is a third diagram showing one of the spectral images in FIG. 6;FIG. 16 is a first diagram illustrating a graphic user interface with afunction of a touch-sensitive panel in FIG. 2; FIG. 17 is a seconddiagram illustrating the graphic user interface with the function of thetouch-sensitive panel in FIG. 2; FIG. 18 is a third diagram illustratingthe graphic user interface with the function of the touch-sensitivepanel in FIG. 2; FIG. 19 is a fourth diagram illustrating the graphicuser interface with the function of the touch-sensitive panel in FIG. 2;and FIG. 20 is a fifth diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2.

FIG. 21 is a sixth diagram illustrating the graphic user interface withthe function of the touch-sensitive panel in FIG. 2; FIG. 22 is aseventh diagram illustrating the graphic user interface with thefunction of the touch-sensitive panel in FIG. 2; FIG. 23 is an eighthdiagram illustrating the graphic user interface with the function of thetouch-sensitive panel in FIG. 2; FIG. 24 is a ninth diagram illustratingthe graphic user interface with the function of the touch-sensitivepanel in FIG. 2; FIG. 25 is a tenth diagram illustrating the graphicuser interface with the function of the touch-sensitive panel in FIG. 2;FIG. 26 is an eleventh diagram illustrating the graphic user interfacewith the function of the touch-sensitive panel in FIG. 2; FIG. 27 is atwelfth diagram illustrating the graphic user interface with thefunction of the touch-sensitive panel in FIG. 2; FIG. 28 is a diagramillustrating white balance processing on a spectral image generated bythe matrix operation unit in FIG. 2; FIG. 29 is a thirteenth diagramillustrating the graphic user interface with the function of thetouch-sensitive panel in FIG. 2; and FIG. 30 is a fourteenth diagramillustrating the graphic user interface with the function of thetouch-sensitive panel in FIG. 2.

FIG. 31 is a diagram showing configuration of board slots on a backsurface of a main body of the endoscope device in FIG. 1; FIG. 32 is afirst diagram illustrating an additional function menu of a functionexpansion substrate inserted into a board slot in FIG. 31; FIG. 33 is asecond diagram illustrating an additional function menu of a functionexpansion substrate inserted into the board slot in FIG. 31; FIG. 34 isa third diagram illustrating an additional function menu of a functionexpansion substrate inserted into the board slot in FIG. 31; FIG. 35 isa diagram showing one example of a keyboard dedicated to wavelengthselection that can be connected to the main body of the endoscope devicein FIG. 2; and FIG. 36 is a diagram showing arrangement in a variationof the color filters in FIG. 4;

In an electronic endoscope device as a living body observation deviceaccording to the embodiment of the present invention, light is radiatedto a living body being a subject from an illuminating light source, anda solid-state image pickup device being an image pickup unit receiveslight reflected from the living body based on the radiated light,photoelectrically converts the received light, so that a image pickupsignal being a color image signal is generated and a spectral imagesignal (hereinafter, also simply referred to as a spectral image) beinga spectral signal is generated corresponding to an optical wavelengthnarrowband image, that is, a band image of a discrete spectraldistribution of said subject, from the image pickup signal by signalprocessing.

As shown in FIG. 1, an electronic endoscope device 100 according to thefirst embodiment includes an endoscope 101 as an observation unit, amain body 105 of the endoscope device and a display monitor 106 as adisplay device. The endoscope 101 is configured mainly with an insertionunit 102 inserted into a subject body, a distal end unit 103 provided ata distal end of the insertion unit 102, and an angle operation unit 104,being provided on an opposite side of the distal end of the insertionunit 102, for instructing bending operation on the distal end unit 103,for example.

In the main body 105 of the endoscope device, pre-determined signalprocessing is performed on an image of the subject acquired by theendoscope 101 being a flexible scope, and the display monitor 106displays a processed image. A display unit of the display monitor 106 isprovided with a touch-sensitive panel 106 a, which realizes a graphicinterface to display various setting screens on the display unit of thedisplay monitor 106, and use a pointing device function of thetouch-sensitive panel 106 a (hereinafter, referred to as atouch-sensitive panel function).

Next, referring to FIG. 2, the main body 105 of the endoscope devicewill be described in detail. FIG. 2 is a block diagram of the electronicendoscope device 100.

As shown in FIG. 2, the main body 105 of the endoscope device isconfigured mainly with a light source unit 41 as an illumination source,a control unit 42 as a signal processing control unit, and a main bodyprocessing device 43. The control unit 42 and the main body processingdevice 43 configure a signal processing control unit for controllingoperation of the light source unit 41 and/or a CCD 21 as an image pickupunit, outputting an image signal to the display monitor 106 being adisplay device, and controlling a touch-sensitive panel function of thetouch-sensitive panel 106 a. The control unit 42 is connected to a datastorage unit 44 for storing various data.

In the description of the present embodiment, the main body 105 of theendoscope device being a single unit includes the light source unit 41and the main body processing device 43 for image processing, forexample. However, the light source unit 41 and the main body processingdevice 43 can be also configured to be removable as separate units fromthe main body 105 of the endoscope device.

The light source unit 41 being an illumination source, which isconnected to the control unit 42 and the endoscope 101, radiates apre-determined light quantity of white light (which can be incompletewhite light) based on a signal from the control unit 42. The lightsource unit 41 includes a lamp 15 as a white light source, an infraredcut filter 15 a, a light quantity limiting filter 16, beinginserted/removed on an optical path, as a spectral characteristicscontrol unit for limiting light quantity in a pre-determined wavelengthregion of white light, a filter insertion/removal driving unit 17 forinserting/removing the light quantity limiting filter 16 on an opticalpath, and a condensing lens 18 for outputting white light.

FIG. 3 shows transmission characteristics of the light quantity limitingfilter 16. For example, when a transmission rate of a blue band is 100%,the light quantity limiting filter 16 limits transmission rates of otherbands to 50%, as shown in FIG. 3.

The endoscope 101 connected to the light source unit 41 via a connector11 comprises an object lens 19 and a solid-state image pickup device 21such as a CCD (hereinafter, simply referred to as a CCD) at the distalend unit 103. The CCD 21 according to the present embodiment is asingle-panel type (a CCD used for a simultaneous type electronicendoscope) and a primary color type. FIG. 4 shows arrangement of colorfilters arranged on an image pickup surface of the CCD 21. The colorfilters arranged on the image pickup surface of the CCD 21 configure acolor separation unit.

As shown in FIG. 2, the insertion unit 102 contains a light guide 14 forguiding light radiated from the light source unit 41 to the distal endunit 103, a signal line for transmitting an image of a subject obtainedby the CCD 21 to the main body processing device 43, a forceps channel28 for treatment and the like. A forceps hole 29 for inserting forcepsinto the forceps channel 28 is provided in a vicinity of the operationunit 104.

The operation unit 104 contains an ID unit 110 for storingclassification information of the endoscope 101. The operation unit 104is also provided with an instruction switch unit 111 for instructingvarious operations on an outer surface. The instruction switch unit 111includes at least a mode changing switch for instructing a spectralimage generation mode, which will be described later, to generate aspectral image with improved S/N.

The main body processing device 43 as a signal processing device for aliving body observation device is connected to the endoscope 101 via theconnector 11 similarly to the light source unit 41. The main bodyprocessing device 43 contains a CCD drive 431 for driving the CCD 21 inthe endoscope 101. The main body processing device 43 also includes aluminance signal processing system and a color signal processing systemas signal circuit systems for obtaining a color image being a normalimage.

The luminance signal processing system of the main body processingdevice 43 includes a contour correction unit 432, being connected to theCCD 21, for correcting a contour of an image pickup signal from the CCD21, and a luminance signal processing unit 434 for generating aluminance signal from data corrected by the contour correction unit 432.The color signal processing system of the main body processing device 43also includes sample hold circuits (S/H circuits) 433 a to 433 c, beingconnected to the CCD 21, for sampling an image pickup signal obtained bythe CCD 21, for example, to generate an RGB signal, and a color signalprocessing unit 435, being connected to outputs of the S/H circuits 433a to 433 c, for generating a color signal.

The main body processing device 43 also includes a normal imagegeneration unit 437 for generating a color image being a single normalimage from the outputs of the luminance signal processing system and thecolor signal processing system. The normal image generation unit 437outputs a Y signal being a luminance signal and an R-Y signal and a B-Ysignal being color difference signals to a display image generation unit439, and generates a normal image signal of a color image being a normalimage displayed on the display monitor 106 by the display imagegeneration unit 439 based on the Y signal, R-Y signal and B-Y signal.

Meanwhile, the main body processing device 43 includes a matrixoperation unit 436 as a spectral signal generation unit for performing apre-determined matrix operation on an RGB signal to which, as a signalcircuit system for obtaining a spectral image signal being a spectralsignal, outputs (RGB signals) of the S/H circuits 433 a to 433 c areinputted. The matrix operation by the matrix operation unit 436 isprocessing to perform addition processing, for example, on color imagesignals, and multiply a matrix obtained by a matrix calculation methoddescribed later.

In the present embodiment, a method using electronic circuit processing(processing by hardware with an electronic circuit) will be described asa method for the matrix operation. However, a method can be alsopossible using numerical data processing (processing by software with aprogram). For implementation, a combination of the methods is alsopossible.

Spectral image signals F1 to F3 being output of the matrix operationunit 436 are subjected to color adjustment operation in a coloradjustment unit 440 being a color adjustment unit to generate spectralcolor channel image signals Rch, Gch and Bch from the spectral imagesignals F1 to F3. The generated spectral color channel image signalsRch, Gch and Bch are sent to RGB color channels R-(ch), G-(ch) andB-(ch) of the display monitor 106 via the display image generation unit439.

The display image generation unit 439 generates a display imageincluding a normal image and/or a spectral image and outputs the displayimage on the display monitor 106, and can display spectral images byswitching between the images. That is, an operator can selectivelydisplay any of a normal image, a spectral color channel image throughthe color channel R-(ch), a spectral color channel image through thecolor channel G-(ch) and a spectral color channel image through thecolor channel B-(ch) on the display monitor 106. The display monitor 106can also be configured to be able to simultaneously display any two ormore images. Particularly, if a normal image and a spectral colorchannel image (hereinafter, also referred to as a spectral channelimage) can be simultaneously displayed, a normal image for generalobservation and a spectral channel image can be easily compared, so thatobservation is possible in consideration of their respective features (anormal image has a feature of a color degree being similar to normalmacroscopic observation and can be observed easily; and a spectralchannel image has a feature that a pre-determined blood vessel, forexample, can be observed that cannot be observed with a normal image),which is very useful to diagnosis.

The following will describe a matrix calculation method for the matrixoperation unit 436 to calculate a matrix.

(Matrix Calculation Method)

FIG. 5 is a conceptual diagram showing a flow of a signal in generatinga spectral image signal corresponding to an image being moreapproximately equivalent to an optical wavelength narrowband image fromcolor image signals (referred to as R, G and B herein for ease ofdescription; however, combination of G, Cy, Mg and Ye is also possiblein a complementary solid-state image pickup device, as described later).Hereinafter, a vector and a matrix are represented in a bold characteror with “ ” (for example, a matrix A is represented as “A (boldcharacter)”, or “A”), while others are represented without characterdecoration.

First, the electronic endoscope device 100 converts color sensitivitycharacteristics as spectral sensitivity characteristics of respective R,G and B image pickup units into numerical data. The R, G and B colorsensitivity characteristics are output characteristics for wavelengthsobtained when an image of a white shooting object is picked up using awhite-light source.

The respective R, G and B color sensitivity characteristics are shown inright of image data as a simplified graph. In the graph, the R, G and Bcolor sensitivity characteristics are represented as n-dimensionalcolumn vectors “R”, “G” and “B”, respectively.

Next, the electronic endoscope device 100 converts characteristics ofnarrowband bandpass filters F1, F2 and F3 for a spectral image withcenter wavelengths λ1, λ2 and λ3 (for example, λ1=420 nm, λ2=540 nm andλ3=605 nm) as basic spectral characteristics of spectral signals to beextracted, for example, three spectral signals into numerical data.Characteristics of the filters are represented as n-dimensional columnvectors “F1”, “F2” and “F3”, respectively.

Based on the acquired numerical data, an optimal coefficient set isobtained to approximate a following relation. That is, matrix elementssatisfying

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack & \; \\{{\left( {R\mspace{31mu} G\mspace{31mu} B} \right)\begin{pmatrix}a_{1} & a_{2} & a_{3} \\b_{1} & b_{2} & b_{3} \\c_{1} & c_{2} & c_{3}\end{pmatrix}} = \left( {F_{1}\mspace{31mu} F_{2}\mspace{31mu} F_{3}} \right)} & (1)\end{matrix}$

should be obtained.

A solution to a proposition of the above optimization is mathematicallygiven as follows: when a matrix representing R, G and B colorsensitivity characteristics is “C”, a matrix representing spectralcharacteristics of a narrowband bandpass filter to be extracted is “F”,and a coefficient matrix to be obtained which executes principalcomponent analysis or orthogonal development (or orthogonaltransformation) is “A”:

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 2} \right\rbrack & \; \\{C = {{\left( {R\mspace{31mu} G\mspace{31mu} B} \right)\mspace{31mu} A} = {{\begin{pmatrix}a_{1} & a_{2} & a_{3} \\b_{1} & b_{2} & b_{3} \\c_{1} & c_{2} & c_{3}\end{pmatrix}\mspace{31mu} F} = \left( {F_{1}\mspace{14mu} F_{2}\mspace{14mu} F_{3}} \right)}}} & (2)\end{matrix}$

Therefore, the proposition shown in the expression (1) is equal to thatto obtain the matrix “A” satisfying a following relation:

[Formula 3]

CA=F  (3)

where for a point sequence number n as spectrum data representingspectral characteristics, n>3, so that the expression (3) is given notas a one-dimensional simultaneous equation, but as a solution to alinear least-squares method. That is, a quasi-inverse matrix can besolved from the expression (3). When a transposed matrix of the matrix“C” is “C”, the expression (3) is as follows:

[Formula 4]

^(t)CCA=^(t)CF  (4)

where “^(t)CC” is an n×n square matrix. Therefore, the expression (4)can be considered as a simultaneous equation of the matrix “A”. Asolution to the equation is given as follows:

[Formula 5]

A=(^(t) CC)^(−1t) CF  (5)

The electronic endoscope device 100 converts a left-hand side of theexpression (3) for the matrix “A” obtained by the expression (5) and canapproximate characteristics of the narrowband bandpass filters F1, F2and F3 to be extracted.

The matrix operation unit 436 generates a spectral image signal from anormal color image signal using the matrix calculated as the above.

Next, operation of the electronic endoscope device 100 according to thepresent embodiment will be described in detail referring to FIG. 2.

In the following, operation of normal image generation will be describedfirst, and operation of spectral image generation will be describedlater.

Normal Image Generation:

First, operation of the light source unit 41 will be described. Based ona control signal from the control unit 42, the filter insertion/removaldriving unit 17 sets the light quantity limiting filter 16 out of aposition on an optical path. Light flux from the lamp 15 is condensed atan inlet end of the light guide 14 being an optical fiber bundleprovided in the connector 11 at a connection unit between the endoscope101 and the light source unit 41 by the condensing lens 18 via theinfrared cut filter 15 a without transmitting through the light quantitylimiting filter 16.

The condensed light flux is radiated into a body of a subject from anillumination optical system provided at the distal end unit 103 throughthe light guide 14. The radiated light flux reflects in the subject andsignals are collected for each color filter shown in FIG. 4 in the CCD21 via the object lens 19.

The collected signals are inputted to the above luminance signalprocessing system and color signal processing system in parallel. Thesignals collected for each color filter are added and inputted to thecontour correction unit 432 of the luminance signal system for eachpixel, and inputted to the luminance signal processing unit 434 aftercontour correction. Luminance signals are generated in the luminancesignal processing unit 434, and inputted to the normal image generationunit 437.

Meanwhile, the signals collected by the CCD 21 are inputted to the S/Hcircuits 433 a to 433 c for each filter, and R, G and B signals aregenerated. Further, the color signal processing unit 435 generates colorsignals from the R, G and B signals. The normal image generation unit437 generates Y signals, R-Y signals and B-Y signals from the luminancesignals and color signals. The display image generation unit 439displays a normal image of the subject on the display monitor 106.

Spectral Image Generation:

Spectral image generation has two generation modes. A first spectralimage generation mode is a mode to prevent light flux from the lamp 15from being transmitted through the light quantity limiting filter 16similarly to the normal image generation. A second spectral imagegeneration mode is a mode to cause light flux from the lamp 15 totransmit through the light quantity limiting filter 16. In a defaultstate, the control unit 42 sets a spectral image generation mode to thefirst spectral image generation mode. When a mode changing switch of theinstruction switch unit 111 is operated, the control unit 42 controlsdriving of the filter insertion/removal driving unit 17, arranges thefilter insertion/removal driving unit 17 on an optical path of lightflux from the lamp 15, and sets the generation mode to the secondspectral image generation mode. As a result, in the second spectralimage generation mode, the light flux from the lamp 15 will betransmitted through the light quantity limiting filter 16.

In the present embodiment, the spectral image generation mode can bealso set to the second spectral image generation mode by operating akeyboard or the touch-sensitive panel 106 a provided on the main body105 instead of the mode changing switch of the instruction switch unit111. The first spectral image generation mode and the second spectralimage generation mode are same in other operation, so the descriptionwill take the first spectral image generation mode as an example.Similar operation to the normal image generation will not be described.

During the spectral image generation in the first spectral imagegeneration mode, the matrix operation unit 436 amplifies and addsoutputs (ROB signals) of the S/HE circuits 433 a to 433 c. The coloradjustment unit 440 performs color adjustment operation on the spectralimage signals F1 to F3 being outputs of the matrix operation unit 436and the spectral color channel image signals Rch, Gch and Bch aregenerated from the spectral image signals F1 to F3. The generatedspectral color channel image signals Rch, Gch and Bch are sent to theROB color channels R-(ch), G-(ch) and B-(ch) of the display monitor 106.

In the above way, the main body processing device 43 can display aspectral image corresponding to a narrowband light observation imageobtained with narrowband light via narrowband bandpass filters F1, F2and F3 with center wavelengths λ1, λ2 and λ3 as shown in FIG. 6 on thedisplay monitor 106.

The following illustrates one example of a spectral image generatedusing the quasi-filter characteristics corresponding to the narrowbandbandpass filters F1, F2 and F3.

As shown in FIG. 7, tissue in a body cavity 51 often has absorberdistribution structures such as different blood vessels in a depthdirection, for example. Many capillary vessels 52 distribute around amucosa surface layer, blood vessels 53, which are larger than thecapillary vessels, distribute in addition to the capillary vessels in anintermediate layer being deeper than the mucosa surface layer, andfurther larger blood vessels 54 distribute in a further deeper layer.

On the other hand, an invasion depth of light in a depth direction intothe tissue in the body cavity 51 depends on a wavelength of the light.For illumination light including a visible region, short wavelengthlight like blue (B) light as shown in FIG. 8 only invades near a surfacelayer due to absorption characteristics and scattering characteristicsin living tissue, is absorbed and scattered in that depth range, andlight emitted from the surface is observed. Green (G) light of a longerwavelength than blue (B) light invades deeper than the range in whichblue (B) light invades, is absorbed and scattered in that range, andlight emitted from the surface is observed. Red (R) light of a longerwavelength than green (G) light reaches a deeper range.

As shown in FIG. 9, since respective wavelength regions of RGB light innormal observation of the tissue in a body cavity 51 overlap,

(1) An image pickup signal subjected to image pickup by the CCD 21through B-band light picks up a band image with superficial layer andintermediate layer tissue information containing much tissue informationin a superficial layer as shown in FIG. 10,(2) An image pickup signal subjected to image pickup by the CCD 21through G-band light picks up a band image with superficial layer andintermediate layer tissue information containing much tissue informationin an intermediate layer as shown in FIG. 11, and(3) An image pickup signal subjected to image pickup by the CCD 21through R-band light picks up a band image with intermediate layer anddeep layer tissue information containing much tissue information in adeep layer as shown in FIG. 12.

The main body 105 of the endoscope device performs signal processing onthe KGB image pickup signals, so that an endoscope image can be obtainedin which color is reproduced as desired or naturally as an endoscopeimage.

The above matrix processing in the matrix operation unit 436 is tocreate a spectral image signal by using a quasi-bandpass filter (matrix)previously generated as the above for a color image signal. For example,the spectral image signals F1 to F3 are obtained using thequasi-bandpass filters F1 to F3 with discrete and narrowband spectralcharacteristics that can extract the desired deep layer tissueinformation as shown in FIG. 6. Since respective wavelength regions ofthe quasi-bandpass filters F1 to F3 do not overlap as shown in FIG. 6,

(4) A spectral image signal F1 through the quasi-bandpass filter F1picks up a band image with the tissue information in the superficiallayer as shown in FIG. 13,(5) A spectral image signal F2 through the quasi-bandpass filter F2picks up a band image with the tissue information in the intermediatelayer as shown in FIG. 14, and(6) A spectral image signal F3 through the quasi-bandpass filter F3picks up a band image with the tissue information in the deep layer asshown in FIG. 15.

For the spectral image signals F1 to F3 acquired in the above manner,the color adjustment unit 440 assigns the spectral image signal F3 tothe spectral color channel image signal Rch, the spectral image signalF2 to the spectral color channel image signal Gch, and the spectralimage signal F1 to the spectral color channel image signal Bch, as anexample of simplest color conversion, and outputs the signals to the RGBcolor channels R-(ch), G-(ch) and B-(ch) of the display monitor 106 viathe display image generation unit 439.

If a color image through the color channels R-(ch), G-(ch) and B-(ch) isobserved on the display monitor 106, it appears as an image as shown inFIG. 16, for example. Large blood vessels are at deeper positions, thespectral image signal F3 is reflected, and a color image havingpre-determined target colors is shown as a red pattern. For a vascularnetwork near an intermediate layer, the spectral image signal F2 isstrongly reflected, so that a color image having pre-determined targetcolors is shown as a magenta pattern. Some of the vascular networks neara mucosa surface are expressed as yellow patterns.

The spectral image signals F1 to F3 depend on spectral sensitivity of anendoscope such as a lens or an opto-electric conversion system inaddition to spectral reflectivity of a shooting object. As such, thecontrol unit 43 reads out an ID being classification information of theendoscope 101 from the ID unit 110 in the operation unit 104, andcorrects the spectral image signals F1 to F3 with a correctioncoefficient depending on the connected endoscope 101 stored in the datastorage unit 44 based on the ID. The present embodiment can beconfigured such that a correction coefficient is stored in the ID unit110 and the control unit 43 reads out an ID and the correctioncoefficient from the ID unit 110.

As described in the above, the spectral image signals F1 to F3 aregenerated through matrices corresponding to the quasi-bandpass filtersF1 to F3, while the quasi-bandpass filters F1 to F3 are characterized bycenter wavelengths λ1, λ2 and λ3. That is, the main body processingdevice 43 sets one center wavelength λ to decide one quasi-bandpassfilter F, and generates a spectral image signal F based on thequasi-bandpass filter F.

According to the present embodiment, a function of the touch-sensitivepanel 106 a can be used to set a center wavelength λ by a graphic userinterface and generate a desired spectral image signal F.

The following will describe the graphic user interface by the functionof the touch-sensitive panel 106 a.

According to the present embodiment, the main body processing device 43displays a setting screen to set a center wavelength of a quasi-bandpassfilter corresponding to a spectral image signal on the observationmonitor 106 including the touch-sensitive panel 106 a as in FIG. 17. Thesetting screen can set a plurality of for example, six centerwavelengths λ11, λ12, λ13, λ21, λ22 and λ23, For example, if a λ11button 201 for starting setting the wavelength λ11 is selected using atouch-sensitive panel function, the main body processing device 43deploys and displays a pop-up window 207 having a plurality ofselectable wavelengths on the observation monitor 106. Then, a setwavelength value of the pop-up window 207 is selected through thetouch-sensitive panel function, so that the main body processing device43 sets the set wavelength value as the wavelength λ11. FIG. 17indicates a state of the main body processing device 43 having set a setwavelength value 425 nm as the wavelength λ11. Operations to set otherwavelengths, i.e., a λ12 button 202, a λ13 button 203, a λ21 button 204,a λ22 button 205 and λ23 button 206 can also set wavelength values to beset using the touch-sensitive panel function on the setting screensimilarly to the wavelength λ11. A spectral image can be colored bysetting set wavelength values as at least three wavelengths (forexample, the wavelengths λ11, λ12 and λ13) on the setting screen.Hereinafter, a colored spectral image is referred to as a color spectralimage.

According to the present embodiment, the setting screen to set a centerwavelength of a quasi-bandpass filter is not limited to as shown in FIG.17, but can be a setting screen including a set table 208 to set aplurality of wavelength sets in which three wavelengths constitutes aset for previous coloring as shown in FIG. 18 as a first variation ofthe present embodiment. If the setting screen in FIG. 18 is displayed onthe observation monitor 106 including the touch-sensitive panel 106 a, adesired wavelength set can be selected from the plurality of wavelengthsets being set in the set table 208 using the touch-sensitive panelfunction.

Alternatively, a select button 209 can be provided, the set table 208can be set by toggling the wavelength sets at each time the selectbutton 209 is operated using the touch-sensitive panel function as shownin FIG. 19 as a second variation of the present embodiment.Specifically, each time the select button 209 is operated using thetouch-sensitive panel function, a set to be set is toggled for selectionas in set 1→set 2→set 3→set 4→set 1→ . . . . FIG. 20 shows the settingscreen when the select button 209 is operated using the touch-sensitivepanel function in the state in FIG. 19, selection of the set 1 as shownin FIG. 19 shifts to selection of the set 2 as shown in FIG. 20 throughan operation of the select button 209.

According to the present embodiment, the display image generation unit439 has display forms to display a color spectral image on the displayscreen of the touch-sensitive panel 106 a (i.e., the observation monitor106) such as: (1) a display form to simultaneously display a normallight observation image and a color spectral image; (2) a display formto display only a color spectral image; and (3) a display form todisplay only a normal light observation image.

In the form to simultaneously display a normal light observation imageand a spectral color image, the main body processing device 43 cansimultaneously display a normal light observation image 210 and acolored color spectral image 211 on the observation monitor 106 by thedisplay image generation unit 439, as shown in FIG. 21. During theabove, the display image generation unit 439 can display thumbnailimages 221 to 226 of spectral images with the six center wavelengthsbeing set in, for example, the above setting screen available to be usedin coloring the color spectral image 211 in addition to the normal lightobservation image 210 and the color spectral image 211. Then, thumbnailimages of three spectral images configuring the color spectral image 211are displayed in a different display form (for example, luminance orcolor tone) from other thumbnail images. According to the presentembodiment, three spectral images can be arbitrarily changed thatconfigure the color spectral image 211 by selecting any of the thumbnailimages 221 to 226 using the touch-sensitive panel function.Specifically, for example when the color spectral image 211 is touched,the thumbnail images 221 to 226 are selectable, and three spectralimages are changed that configure the color spectral image 211 byselecting thumbnail images of spectral images with three centerwavelengths for coloring. FIG. 21 shows a state of the color spectralimage 211 being generated through three spectral images with the centerthe wavelengths λ11, λ12 and λ13. FIG. 22 shows a state of the colorspectral image 211 being generated through three spectral images withthe center wavelengths λ12, λ21 and λ23.

If the touch-sensitive panel 106 a displays only a normal light image asshown in FIG. 23, the main body processing device 43 can display apainting setting window 230 to change a color tone of the normal lightimage by superposition. The device 43 can change the color tone of thenormal light image by the user touching an indicator 230 a of thepainting setting window 203 using the touch-sensitive panel function tochange a ratio of red to blue.

In the display form to display only a color spectral image, the paintingsetting window 203 is available as a wavelength selection window 230 fora center wavelength λ, as shown in FIG. 24. When the window 203 is usedas the wavelength selection window 230, the indicator 230 a showswavelengths, each display point of the indicator 230 a is assigned witha plurality of center wavelengths, three spectral images configuring thecolor spectral image 211 can be selected in the wavelength selectionwindow 230 by selecting three display points in the indicator 230 a.When three spectral images are selected, a luminance setting window 231to set luminance of a spectral image is displayed below the wavelengthselection window 230, so that luminance of a spectral image with eachwavelength can be arbitrarily set.

In the display form to display only a color spectral image, the mainbody processing device 43 can display spectral reflectivity 242 from asubject in a vicinity of a color spectral image 241 as a graph, as shownin FIG. 25. For example, the wavelengths λ1, λ2 and λ3 of three spectralimages configuring the color spectral image 241 are presented on thespectral reflectivity 242, the wavelengths λ1, λ2 and λ3 can varythrough the touch-sensitive panel function; when the wavelengths λ1, λ2and λ3 vary, the three spectral images configuring the color spectralimage 241 change accordingly.

When a freeze switch (not shown) of the instruction switch unit 111provided in the operation unit 104 of the endoscope 101, for example, isoperated in the display form to display only a color spectral image, acolor spectral image being displayed as a moving image becomes thestatic freeze color spectral image 241, as shown in FIG. 26. The mainbody processing device 43 displays thumbnail images 221 to 226 of thespectral images with the six center wavelengths being set in, forexample, the above setting screen available to be used in coloring thefreeze color spectral image 241 in a vicinity of the freeze colorspectral image 241. Moreover, the thumbnail images of the three spectralimages configuring the freeze color spectral image 241 are displayed ina different display form (for example, different luminance or colortone) from other thumbnail images. According to the present embodiment,three spectral images configuring the freeze color spectral image 241can be arbitrarily changed by selecting the thumbnail images 221 to 226using the touch-sensitive panel function and operating a selectiondecision button 243 as shown in FIG. 27. Further, according to thepresent embodiment, the color spectral image 241 of a moving image ofthe three spectral images selected from the thumbnail images 221 to 226can be displayed by operating a confirmation button 244 using thetouch-sensitive panel function. According to the present embodiment, thecolor spectral image 241 of the moving image of the three spectralimages selected from the thumbnail images 221 to 226 can also beautomatically displayed only by an operation of the selection decisionbutton 243, instead of providing the confirmation button 244.

As described in the above, according to the present embodiment, the mainbody 105 of the endoscope device can arbitrarily change three spectralimages configuring a color spectral image. In that case, white balanceprocessing for the three spectral images is changed simultaneously. Inparticular, the main body 105 of the endoscope device discretely storesa three-dimensional data table with three wavelengths λi, λj and λk asaxes as shown in FIG. 28 previously in the data storage unit 44, forexample. Each voxel of the three-dimensional data table stores weightingfactors (kx, ky, kz) used for the white balance processing as voxeldata. The main body 105 of the endoscope device performs the whitebalance processing on three spectral images Fl, Fm and Fn withwavelengths λil, λjm and λkn through an operation “color spectralimage=kx×Fl+ky×Fm+kz×Fn”, for example.

The main body 105 of the endoscope device discretely stores thethree-dimensional data table to reduce a storage capacity of the datastorage unit 44 for storing respective voxel data. As such, theweighting factors among the voxel data are calculated through generallinear interpolation for the white balance processing.

In the display form to display only a normal light observation image,the main body processing device 43 designates a spectral image displayframe 281 on the normal light observation image 210 as shown in FIG. 29,so that the device 43 can display a spectral image of the region bysuperposition in a region of the designated spectral image display frame281. A size and position of the spectral image display frame 281 can bearbitrarily changed by the touch-sensitive panel function, as shown inFIG. 30.

According to the present embodiment, configuration of a spectral imageis set using a wavelength as a setting parameter, but the presentinvention is not limited thereto. Instead, the designation can be doneusing depth information being an invasion depth of light as a settingparameter, or the designation can be done using a function name such asblood vessel highlighting as a setting parameter.

Further, according to the present embodiment, configuration of aspectral image being optimal to observation based on an organ to beobserved can be automatically designated. In that case, a method ofdesignating configuration of a spectral image based on an organ includesa method of identifying and designating an organ for which the endoscope101 is used with an ID from the ID unit 110 in the operation unit 104, amethod of designating by a menu switch on the touch-sensitive panel 106a, a method of designating by reading data of a PC card recordingpatient information, or a method of automatically recognizing an organby performing image processing on a normal light observation image by ascene understanding module, for example.

The main body 105 of the endoscope device according to the presentembodiment is provided with a plurality of board slots 300 on a backsurface into which function expansion substrates for function expansioncan be inserted, as shown in FIG. 31. Meanwhile, the control unit 44displays a menu window 260 as shown in FIG. 32 on the touch-sensitivepanel 106 a to deploy executable functions. Assume that defaultfunctions of the control unit 44 without a function expansion substratebeing inserted can be classified to four basic functions, for example,the functions are switchable using tags 261 of menus 1, 2, 3 and 4 onthe menu window 260. The menu window 260 includes menu tags 262 for aplurality of function expansion substrates in addition to the tags 261of menus 1, 2, 3 and 4. When no function expansion substrate is set inthe board slots 300 as default, the menu tags 262 are for empty menus,as shown in FIG. 33. However, when a function expansion substrate isinserted into the board slots 300, the control unit 44 can deploy anadditional function menu window of functions of the inserted functionexpansion substrate from the menu window 260 through a tag 262 a of amenu 5, as shown in FIG. 34.

The additional function menu window is configured in software. As such,when a function expansion substrate is inserted, the control unit 44identifies the function expansion substrate, and a menu window withsimilar configuration to the basic functions is automatically generated,so that a version of software does not need to be changed, or a versionof the software is easily upgraded.

According to the present embodiment, the operation is performed throughthe touch-sensitive panel 106 a, and specifications can be easilychanged without changing hardware, but by upgrading a version of thesoftware.

According to the present embodiment, not all of the operations must beperformed through the touch-sensitive panel 106 a, but the operationscan be performed using a pointing device such as a trackball or mouse,or a wavelength of a spectral image can be set through a keyboard 270dedicated to select a wavelength, for example, as shown in FIG. 35.Moreover, a wavelength setting function can be assigned to a functionkey of a general keyboard.

As described in the above, according to the present embodiment, in adefault state of a spectral image generation mode being the firstspectral image generation mode, the display monitor 106 can selectivelydisplay a normal light observation image and a spectral image byprioritizing a image quality of a normal light observation image.Further, the mode changing switch of the instruction switch unit 111switches the spectral image generation mode to the second spectral imagegeneration mode through operation, transmit light flux from the lamp 15through the light quantity limiting filter 16, and decreases lightquantity of light in other wavelength bands to a half of light in a bluewavelength band, so that the display monitor 106 can selectively displaythe normal light observation image and the spectral image byprioritizing image quality of a spectral image.

In other words, by setting the spectral image generation mode to thesecond spectral image generation mode, and transmitting light flux fromthe lamp 15 through the light quantity limiting filter 16, a spectralimage in a blue wavelength band can be improved to image informationwith a similar S/N to spectral images in other wavelength bands, forexample.

According to the present embodiment, the light quantity limiting filter16 is configured to be insertably removable on an optical path. However,the filter 16 can also be permanently provided on an optical path.Moreover, a color filter provided for the CCD 21 can have similarspectral characteristics to a light quantity limiting filter, therebyomitting the light quantity limiting filter 16.

As a variation of the present embodiment, complementary color filterscan be used instead of using the RGB primary color filters. Arrangementof the complementary filters is configured with G, Mg, Ye and Cyelements as shown in FIG. 36. A relation between the respective elementsof the primary color filters and the respective elements of thecomplementary color filters is: Mg=R+B, Cy=G+B and Ye=R+G.

According to the variation, all pixels of the CCD 21 are read out, andsignal processing or image processing is performed on an image from eachcolor filter. If the complementary filters are used, it is needless tosay that the S/H circuit shown in FIG. 2 is not for R, C and B, but forG, Mg, Cy and Ye, but living body spectral reflectivity can beapproximated with three basic spectral characteristics for four or lessunits. Accordingly, a dimension to calculate an estimated matrix ischanged from three to four.

Second Embodiment

FIGS. 37 to 43 relate to a second embodiment of the present invention.FIG. 37 is a block diagram showing configuration of an electronicendoscope device; FIG. 38 is a diagram showing configuration of an RGBrotating filter in FIG. 37; FIG. 39 is a diagram showing spectralcharacteristics of light that is transmitted through the RGB rotatingfilter in FIG. 38 when a light quantity limiting filter in a firstspectral image generation mode is not on an optical path; FIG. 40 is adiagram showing spectral characteristics of light that is transmittedthrough the RGB rotating filter in FIG. 38 when the light quantitylimiting filter in a second spectral image generation mode is on anoptical path; FIG. 41 is a block diagram showing configuration of avariation of the electronic endoscope device in FIG. 37; FIG. 42 is adiagram showing configuration of an RGB rotating filter in FIG. 41; andFIG. 43 is a diagram showing configuration of a variation of the RGBrotating filter in FIG. 38.

The second embodiment is almost same as the first embodiment. As such,only different points will be described and the same components aregiven same numerals and will not be described.

The present embodiment differs from the first embodiment mainly in thelight source unit 41 and the CCD 21. According to the first embodiment,the CCD 21 is provided with the color filter shown in FIG. 4, and aso-called simultaneous type is used in which the color filter generatesa color signal. On the other hand, according to the present embodiment,so-called frame sequential type is used for illuminating illuminationlight in an RGB order to generate a color signal.

As shown in FIG. 37, in the light source unit 41 according to thepresent embodiment, light via the lamp 15, the infrared cut filter 15 aand the light quantity limiting filter 16 is transmitted through an RGBfilter 23. Similarly to the first embodiment, the light quantitylimiting filter 16 is insertably removable on an optical path. The RGBrotating filter 23, which is connected to an RGB rotating filter controlunit 26, rotates at a pre-determined rotation speed.

The RGB rotating filter 23 is configured with an R filter unit 23 r fortransmitting R band light, a G filter unit 23 g for transmitting G bandlight, and a B filter unit 23 b for transmitting B band light, as shownin FIG. 38. FIG. 39 shows spectral characteristics of light transmittingthe RGB rotating filter 23 in the first spectral image generation mode,i.e., when the light quantity limiting filter 16 is not on an opticalpath. FIG. 40 shows spectral characteristics of light being transmittedthrough the RGB rotating filter 23 in the second spectral imagegeneration mode, i.e., when the light quantity limiting filter 16 is onan optical path.

In operation of the light source unit according to the presentembodiment, unnecessary infrared components of light flux outputted fromthe lamp 15 are cut in the infrared cut filter 15 a, and light fluxbeing transmitted through the infrared cut filter 15 a selectivelypasses through the light quantity limiting filter 16 and is transmittedthrough the RGB rotating filter 23, so that the light flux is outputtedfrom the light source unit as R, G and B illumination lights at eachpre-determined time. The respective illumination lights reflect in asubject and received by the CCD 21. Signals obtained by the CCD 21 aredistributed by a switch unit (not shown) provided for the main body 105of the endoscope device depending on radiation time, and inputted to theS/H circuits 433 a to 433 c, respectively. That is, if illuminationlight is radiated from the light source unit 41 via an R filter, thesignals obtained by the CCD 21 are inputted to the S/H circuit 433 a.The other operation is similar to the first embodiment and will not bedescribed.

According to the present embodiment, similarly to the first embodiment,by setting a spectral image generation mode to the second spectral imagegeneration mode and transmitting light flux from the lamp 15 through thelight quantity limiting filter 16, a spectral image in a blue wavelengthband can be improved to image information with similar S/N of spectralimages in other wavelength bands, for example.

According to the present embodiment, the light quantity limiting filter16 is configured to be insertably removable on an optical path, but theembodiment is not limited thereto. Instead, the RGB rotating filter 23can be configured as shown in FIG. 42 to omit the light quantitylimiting filter 16 as shown in FIG. 41.

That is, the rotating filter 23 is configured in a disc shape and has adouble structure centering on a rotation axis as shown in FIG. 42. On anoutside diameter part of the filter 23, an R filter unit 23 r 1, the Gfilter unit 23 g 1 and the B filter unit 23 b 1 are arranged thatconfigure a first filter set to output frame sequential light with thespectral characteristics as shown in FIG. 39. On an inside diameterpart, an R′ filter unit 23 r 2, a G′ filter unit 23 g 2 and a B filterunit 23 b 2 are arranged that configure a second filter set to outputframe sequential light with the spectral characteristics as shown inFIG. 40.

For the rotating filter 23, the control unit 42 controls driving of arotating filter motor 26 and rotates the motor 26 as shown in FIG. 41,and the control unit 42 moves the filter 23 in a diameter direction(moves perpendicularly to an optical path of the rotating filter 23, andselectively moves the first filter set or second filter set of therotating filter 23 on the optical path) through a filter switch motor 17a.

According to the present embodiment, the three R, G and B band framesequential lights are radiated, but the embodiment is not limitedthereto. Instead, the rotating filter 23 can be a rotating filter fortransmitting multiband (four or more bands) frame sequential lights 11,12, 13 and 14 in four different bands as shown in FIG. 43, for example,and for radiating multiband frame sequential lights.

In that case, a spectral image is estimated as in expressions (6) to (8)from four band signals.

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 6} \right\rbrack & \; \\{{\begin{pmatrix}{F\; 1} \\{F\; 2} \\{F\; 3}\end{pmatrix} = {K\begin{pmatrix}{I\; 1} \\{I\; 2} \\{I\; 3} \\{I\; 4}\end{pmatrix}}}{K = \begin{pmatrix}k_{1} & k_{2} & k_{3} & k_{4} \\l_{1} & l_{2} & l_{3} & l_{4} \\m_{1} & m_{2} & m_{3} & m_{4}\end{pmatrix}}} & (6)\end{matrix}$

The expression (6) can generate color spectral images with threewavelengths from four band signals.

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 7} \right\rbrack & \; \\{{{F\; 1} = {N\begin{pmatrix}{I\; 1} \\{I\; 2} \\{I\; 3} \\{I\; 4}\end{pmatrix}}}{N = \left( {n_{1}\mspace{31mu} n_{2}\mspace{31mu} n_{3}\mspace{31mu} n_{4}} \right)}} & (7)\end{matrix}$

The expression (7) can generate a monochrome spectral image with asingle wavelength from four band signals.

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 8} \right\rbrack & \; \\{{\begin{pmatrix}{F\; 1} \\{F\; 2} \\{F\; 3} \\{F\; 4}\end{pmatrix} = {O\begin{pmatrix}{I\; 1} \\{I\; 2} \\{I\; 3} \\{I\; 4}\end{pmatrix}}}{O = \begin{pmatrix}o_{1} & o_{2} & o_{3} & o_{4} \\p_{1} & p_{2} & p_{3} & p_{4} \\q_{1} & q_{2} & q_{3} & q_{4} \\r_{1} & r_{2} & r_{3} & r_{4}\end{pmatrix}}} & (8)\end{matrix}$

The expression (8) can generate spectral images with four wavelengthsfrom four band signals, and the display image generation unit 439selects three of the four spectral images to generate a color spectralimage.

The above configuration to radiate multiband frame sequential light canestimate spectral images from four band signals, so that the spectralimages can be estimated more accurately.

The above configuration to radiate multiband frame sequential lights canrealize multiband lights in different bands using a multicolor LED orLD.

The present invention is not limited to the above embodiments. Variouschanges and alterations can be made without deviating from the scope ofthe present invention.

1. A living body observation device comprising a signal processingcontrol unit for controlling operation of an illumination source forirradiating a living body being a subject with light and/or an imagepickup unit for photoelectrically converting light reflected from theliving body based on the illumination light from the illumination sourceand for generating an image pickup signal, and for outputting the imagepickup signal to a display device, the living body observation deviceincluding: a spectral signal generation unit for generating a spectralsignal corresponding to a band image of a discrete spectral distributionof said subject from the image pickup signal by signal processing; and acolor adjustment unit for adjusting a color tone for each of a pluralityof bands forming the spectral signal when the spectral signal isoutputted to the display device, wherein a spectral characteristicscontrol unit for controlling spectral characteristics of light on anoptical path is further provided on the optical path from theillumination source to the image pickup unit.
 2. The living bodyobservation device according to claim 1, wherein: the spectralcharacteristics control unit is a spectral intensity control unit forcontrolling spectral intensity characteristics of the illumination lightand/or an image pickup device spectral sensitivity control unit forcontrolling spectral sensitivity characteristics of an image pickupdevice in the image pickup unit.
 3. The living body observation deviceaccording to claim 1, wherein: the spectral characteristics control unitincreases intensity and/or sensitivity in a pre-determined wavelengthregion compared to intensity and/or sensitivity in other wavelengthregions.
 4. The living body observation device according to claim 2,wherein: the spectral characteristics control unit increases intensityand/or sensitivity in a pre-determined wavelength region compared tointensity and/or sensitivity in other wavelength regions.
 5. The livingbody observation device according to claim 1, wherein: the spectralcharacteristics control unit increases intensity and/or sensitivity in ablue wavelength region compared to intensity and/or sensitivity in otherwavelength regions.
 6. The living body observation device according toclaim 2, wherein: the spectral characteristics control unit increasesintensity and/or sensitivity in a blue wavelength region compared tointensity and/or sensitivity in other wavelength regions.
 7. The livingbody observation device according to claim 1 including a signalgeneration control unit for controlling the spectral signal generationunit through a touch-sensitive panel function, wherein: the displaydevice includes the touch-sensitive panel function.
 8. The living bodyobservation device according to claim 2 including a signal generationcontrol unit for controlling the spectral signal generation unit througha touch-sensitive panel function, wherein: the display device includesthe touch-sensitive panel function.